Psychological factors have been implicated in both the development of coronary artery disease and cardiac arrhythmias. However, the pathophysiological link between behavior and heart disease has yet to be established. Alterations in the regulation of coronary blood flow during acute emotionally stressful situations may contribute significantly to this process. I have recently demonstrated that a controlled behavioral stress will elicit an alpha-adrenergic receptor mediated coronary vasoconstriction (4,5). In a similar manner, it has been demonstrated that during the administration of the cold pressor test, patients with pre-existing coronary artery disease exhibited a significantly greater increase in coronary vascular resistance than did healthy controls (12,13). Thus, pre-existing coronary vessel disease may exacerbate this behaviorally induced coronary vasoconstriction, possibly triggering a vasospastic occlusion of the vessel. It is, therefore, the purpose of the proposed series of experiments to investigate the interaction between psychological stress and myocardial ischemia, infarction, or vessel stenosis on coronary blood flow regulation. Briefly, a multidisciplinary approach using behavioral, physiological and pharmacological techniques will be employed. Classical aversive conditioning which produces a stable and stereotypic cardiovascular response pattern will serve as a model of stress. The mechanisms mediating the coronary response will be determined by the careful application of specific pharmacological and surgical treatments. In addition, this model presents the opportunity to investigate the interaction between myocardial ischemic injury and behavioral stress on arrhythmogenesis.